Generator output reversing switch



Jan., 22, i957 H. J. WIEDEN GENERATOR OUTPUT REVERSING SWITCH FiledMarch 7, 1955 GENERATOR OUTPUT REVERSNG SWITCH Applikation March 7,1955, Serial No. 492,727

15 Claims. (Cl. 206m-61.39)

This invention relates to improved reversing switches, for reversing theoutput circuit or circuits from a generator in response to reversals inthe direction of rotation of the generator rotor.

There are various situations in which it is desirable to employ agenerator adapted to be driven in either of two opposite rotarydirections, and yet which will produce the same type and direction ofcurrent in an output circuit under both operating conditions. Forinstance, it is desirable in railroad cars to employ generators whichwill operate when the car is going either forwardly or in a reversedirection. The general object of the present invention is to provide animproved reversing switch for automatically reversing the generatoroutput in such a situation. Preferably, the switch is capable offunctioning in conjunction with a three phase alternator, to reverse thephase relationship between the three output lines upon a change indirection of operation of the al* ternator.

A switch embodying the invention includes two sets of contacts one otwhich is rotatably shiftable relative to the other between differentpredetermined positions. Such rotary shifting of one set of contacts iseffected automatically when the direction of generator operation isreversed. The shitting may be eiiected by means of an actuatingassembly, including a pawl or pawls which act to engage shouldersassociated with the movable contacts to turn them as the direction ofgenerator rotation is reversed. These pawls may be automaticallyreleased by a suitable camming part when a shifting movement iscompleted, and during subsequent operation vof the generator the pawlsmay be centritugally held in entirely inactive positions.

A particular feature of the invention resides in the provision of meansfor protecting the contacts against excessive wear or rubbing during therotary shifting movement of the movable contacts. Specically, l providemeans acting to retract one set of contacts, preferably the rotatingones, axially away from the other set of contacts during the rotaryshifting movement. Such retraction may be eiiected by cam means actingto cam the movable contacts axially away from the other contacts as aresult of and during their rotary movement.

rlie rotating contacts may be carried by a rotatably shiftable carriermember or plate, and may be mounted for limited and spring resistedmovement relative to that carrier. T he carrier may be bodilydisplaceable axially by the cam means, and may be yieldingly urgedtoward the stationary contacts by a suitable spring. Preferably, thestationary contacts are mounted to a stationary plate or member which ismounted opposite and in spaced relation to an end of the generatorshaft. ri`he rotating contact carrier is then positioned axially betweenthe stationary plate and the shaft end, with the pawl type actuatingunit typically being attached directly to the shaft.

The above and other features and objects of the present invention willbe better understood from the follow- States Patent f* 2,778,897Patented Jan. 22,

ICC

ing detailed description of the typical embodiment illustrated in theaccompanying drawing in which:

Fig. 1 is an axial section through an alternator output reversing switchconstructed in accordance with the invention;

Fig. 2 is a view taken along line 2-2 of Fig. l;

Fig. 3 is a transverse section taken along line 3-3 of Fig. l;

Fig. 4 is a fragmentary view taken along line 4 4 of Fig. 1; and

Fig. 5 is a fragmentary sectional View similar to Fig. l, but showingthe switch assembly during a shifting movement.

In the drawings, I have fragmentarily represented at 1t) a three phasealternator, having the usual outer housing 11, from an end of whichthere projects the alternator shaft 12. Shaft 12 is of course mountedfor rotation within housing 11, as by means of a pair of ball bearings13 (only one shown). The alternating current generated by the alternator1t) flows from the alternator windings through three lines 14, 15 and 16to a reversing switch generally indicated at 17, and leaves that switchthrough three output lines 18, 19 and 20. The alternator i@ is adaptedto be rotatively driven in either of two opposite rotary directions, andthe purpose of switch assembly 17 is to reverse the connections betweenalternator output lines 14, 15 and 16 and lines 18, 19 and 2t) when thedirection of rotation is reversed, to thus always maintain the samephase relation between the currents flowing within lines 13, 19 and 20.

The reversing switch assembly 17 includes a main mounting plate 21attached, as by screws 22, to alternator housing 11. The various partsof reversing switch 17 are carried by plate 21, and may be protected byenclosure within a switch housing 23, typically secured to plate 21 byscrews 22. The stationary contacts of the switch assembly are carried bya plate 24, and the movable contacts are carried by a plate 25 which isrotatable relative to plate 24 and the stationary contacts through 18()degrees. The rotary plate 25 is shiftable relative to stationary plate24 by means of a pair of spring urged pawls 26, which are carried by amounting bracket 27 attached to the end of alternator shaft 12.

The stationary plate 24 is preferably formed of a suitable electricallyinsulative material, such as a suitable rigid plastic material, andextends directly transversely of the axis a of the alternator shaft.Plate 24 is mounted in spaced parallel relation to plate 21, at alocation opposite the end of shaft 12, by a number of parallel mountingscrews 28 rigidly attached at rst ends 29 to plate 21, and projectingoutwardly therefrom. Elongated tubular spacing sleeves 3i? may beprovided about screws 28, to space plate 24 from plate 21. Nuts 31 atthe outer ends of screws 28 retain plate 24 in its illustrated mountedposition on the screws.

Plate 24- carries five electrical contacts which are engaged by themovable contacts carried by movable plate 25. These stationary contactson plate 24 include a first set of three contacts 32, 33 and 34 and asecond and essentially diametrically opposite set of two contacts 35 and35. Each of the tive contacts 32 through 36 comprises a screw likemember yhaving a threaded stem 37 extending through plate `24 and havingan enlarged diameter head 33 which is contained within a counterbore iu'the surface of plate 24. The contact face 39 of each element 37preferably is iiush with the inner surface of plate 2li. Each of thecontact elements is retained to plate 24 by a nut 4t) at the `outer sideof the plate, with the various leads being attached to the outerthreaded portions of the contacts, and being retained thereto byadditional nuts 41. An additional terminal 42, constructed the same asthe various stationary contacts 32 through 36, is attached `to'plate 24at a location such 4that itis never engaged by any of the movablecontacts `carried by plate 25. This 'terminal 42 is utilized merely forconnecting together two of the lead lines, which need not -be-reversedwhenshaft 12 is actuated. For instance, 4lines 16 and yZtl may both beattached to 4terminal 42, so that the current-from line-16 always leavesthe `switch mechanism through line 20 regardless vof the position ofmovable contact plate 25.

The other twolines y14 and 15 fromt'he alternator are connectedtostationary contacts 32 and 33, respectively. A jumper line 43electrically connects contact 34 to con- 'tact 33 and thus to line 15.The output lines 18 and A19 are connected to stationary contacts 35 and36.

The movable contact carrying plateiscircular, and

plates extends transversely of axis a, ,is essentially circularvand isformed of an electrically conductive material, typically steel.

Parts 25 and 44 are mounted for rota-ry movement about a shaft 45, whichis stationarily attached to and projects inwardly from plate v24. Shaft45 is axially aligned with shaft 12 of the alternator. 'Plate 44 has a'central opening 49 with a diameter corresponding essentially to thediameter of shaft 45, to mount plates 25 and 44 for -the desiredlr-otary movement, aswell as for limited axial movement along shaft 45.Plates 25 yand 44 a-re yieldingly urged axially toward plate 24 by acoil spring 47 disposed about shaft 45 and bearing at opposite endsagainst a shaft carried washer 46 and plate 44. The inner opening 48 inplate 25 may be considerably larger in diameter than opening 49 in plate44, to pass spring 47 through plate 25 and into engagement with plate`44. v

Movable plate 25 carries six contacts, including a first set of threecontacts designated numbers 5.0, 51 and 52, anda second vset ofdiametrically opposed contacts 53, 54 and 55. Each of these contacts50throughSS comprises an elongated member having a shaft portion 56extending through and axially movable .within a guiding portion 57 inplate At its end next. to plate 24, each yof the ce tacts 5. through 55has van enlarged diameter head '58; for engaging `one of the .stationarycontacts 3.2 through `36V to closefan electrical circuit. -Coil springs59 yieldingly urge the movable .contactsaxially toward plate 24 andrelative to plates 25 and 44. Head 60 at the other ends of the movablecontacts limit suc'h axial movement reltaive to plates 25 yand 44, andserve as terminals to which threejumper lines 61, 62 and 63 between thevarious movable contacts are connected.

A first of the jumper lines 6.1 electrically connects contacts 5t) and53. A second jumper line .62 interconnects contacts 51 Vand 55, whilethe third line 63 connects together contacts 52 land54. Inoue of its'two rotary positions, the three movablecontacts 50, 51 and 52 engagestationary contacts 32., 33. and 34, while movable contacts 53 and .54engage stationary contacts 35 and 36. In a second rotary position,offset 189 degrees from the iirst, movable contacts 53, 54 and 55.engage stationary contacts 34, 333 and 32, respectively; while movablecontacts 51and52 engage stationary contacts 36 and 35 respectively.

The movable contacts and their carrying d-isc 25 are adapted to beyieldingly retained in either of the two above mentioned rotarypositions relative to plate 24 by means of a earn element 64. This camelement also serves the function .of axially shifting or retracting themovable contact str-uctureaway from the stationary contact plate 24during rotary shifting of the movable conby a member of reduceddimension tabs or lingers 68 n extending through openings in plate 24and turned at rtheir outer ends 67.

Axially opposite -the cam plate `or element 64, plate 44 has twoparallel elongated portions thereof deformed axially toward plate 64 andto essentially V-shaped sectional coniiigurations corresponding to thedetent recess or cam surfaces 65 of element 64. As will be understood,portions 66 of pla-te 44 are urged axially into the detent recess ofplate `64 by spring 47, to thus yieldingly retain plates 25and 44 ineither of two rotary positions odset circular degrees. Also, when plates25 and 44 are turned by the mechanism later to be described, theengagement of V-shaped element 66 with cam surfaces 64 acts to camplates 25 and `44 and the carried movable contacts axially away fromplate 24, so that the movable contacts are out of engagement with plate24 and the stationary contacts cari-red thereby during `the turningmovement.

'The part 27, for rotatably shifting the movable contacts between theirtwo positions, is formed of sheet material deformed to the illustratedLl-shaped or channel shaped configuration. At a central location,element 27 is permanently and rigidly attached to the end of shaft l2,as by a bolt 69 screwed into the end of the shaft. Element 27 extends inopposite transverse directions from shaft l2, and carries at twodiametrically opposite locations a pair of pawls 26, which are pivotallymounted to element 27 by a pair of pins 76 extending between theopposite side portions of channel shaped member 27. Pawls 26 haveportions 26a projecting essentially axially topositions along theoutside of plates 24 and 44, for rotatively shifting these plates inresponse to a reversal in the direction of rotation of shaft i2.Portions 26a of pawls26 are adapted to be centrifugally urged radiallyoutwardly out of engagement with plates 25 and 44 when shaft l2 turns ata substantial speed. These portions 26a of the pawls are yieldinglyVurged radially inwardly into engagement with lplate 44, when thealternator is not turning at a substantial rate of speed, by a pair ofsprings 71 disposed about pins 70 and having their opposite ends bearingagainst pawls 26 and a pair of transverse pins 72 carried by element 27.Pins 72 also act tolirnit the radially outward movement of pawls 26 bycentrifugal force.

Portions 26a of pawls 26 act to engage a pair of radially extendingshoulders 73 and 74 formed on plate 44 at substantially diametricallyopposite locations. These shoulders 73 and 74 extend radially between areduced diameter portion 75 of plate 44 (of a diameter substantiallyequal to plate 25) and an enlarged diameter portion 76 of plate 44.

When shaft 12 and the carried pawls 26 are turning in one rotarydirection, one of these pawls will engage shoulder 73 to turn plates 25and 44 and the carried contacts in a first rotary direction. When thedirection of shaft rotation is reversed, one of the pawls engagesshoulder 74 to turn plates 25 and 44 and the carried contacts in thereverse rotary direction. In either case, this rotation of the discs 25and 44 and the contacts continues until the engaged shoulder 73 or 74reaches a bottom position (the position of shoulder 74 in Fig. 3) atwhich position the pawl which has been doing the turning is cammedradially outwardly by a pawl release cam 77, so that the pawl may thencontinue to turn without inducing further rotation of the movablecontact strucarrasar ture. This release cam 77 may be ot' thesubstantially V-shaped conguration shown, presenting two oppositelydisposed outer cam surfaces 78 and 79 which each extend radiallyoutwardly as they extend circularly about the axis u, to thus effect thedesired radially outward deliection of pawls 26 when turning in eitherdirection. As will be apparent from the drawings, shoulders 73 and 74are offset slightly from true diametrically opposite positions, in orderto allow for the width of the engaging pawls 26. Cam plate '77 may beattached to stationary plate 24 by a pair of tabs Si) extending fromelement 77 through openings in plate 24, with these tabs being turned atthe outer side of plate 24.

To now describe the operation of the illustrated reversing switch,assume that the rotor of alternator 10, and therefore shaft 12, areturning in a first rotary direction in which shoulder 73 of plate 44 isin its upper position, and shoulder 74 is in the lower position adjacentpawl release cam 77. in this condition, the reversing switch places line14 in contact with line 1S through engagement of movable contact St)with stationary contact 32, and engagement of movable contact 53 withstationary contact 35. The connection between movable contacts 50 and S3to complete this circuit is of course formed by jumper line 6l.Similarly, a circuit is closed from line ILS to line i9 through jumperline 43, contacts 34 and 52, jumper line 63, and contacts 54 and 36. Thethird line 16 from the alternator is of course connected directly tooutput line 20.

if the direction of rotation of the alternator and its shaft l2 is thenreversed, the portion 26a of one of the pawls 26 will move intoengagement with upper transverse shoulder 73 of plate 44, and as theshaft and pawl turn, will correspondingly turn plate 44 and the attachedplate 25' and movable contacts 5t) through 55 through approximately i8()degrees. Such turning of the movable contact structure will continueuntil shoulder 73 moves to a lowermost position adjacent pawl releasecam 77, at which position cam 7'7" will deiiect the pawl radiallyoutwardly out of engagement with shoulder i3, so that the shaft l2 maycontinue to turn without further movement of the rotary contactstructure. The speed of rotation will of course remain slow enoughduring the rst one-half turn to assure against centrifugal actuation ofpawl 26 out of engagement with shoulder 73 before the latter has beenturned through 180 degrees. Subsequently, of course, the speed willincrease to a condition in which the pawls are centrifugally actuatedradially outwardly, so that they do not contact plate 44 or cam 77 asthey turn. lf the direction of rotation is again reversed, one of thepawls will engage the shoulder 74 which has now been actuated to anuppermost position, and will turn the rotary contact structure throughapproximately 180 degrees, at which position the pawl will be dellectedradially outwardly by carn element 77, and the rotation of plate 44 willthen cease. in the position in which shoulder 73 is adjacent pawlrelease cam 77, the electrical circuits are closed through switch 17 asfollows. Line 14 from the alternator is connected to line 19 throughcontacts 32 and 55, jumper line 62, and contacts 51 and 36. Also, line1.5 is placed in communication with line i8 through contacts 33 and 54,jumper line 63, and contacts 52 and 35. Thus, the connections from lines14 and to lines L3 and 19 are reversed from their previous condition, tomaintain the output in lines 13, 19 and 20 in the same phaserelationship as before the shifting movement of the rotary Contactstructure, even though the direction of rotation of shaft 12 has beenreversed.

As plate dfi is turned through 180 degrees between its two circuitclosing positions, the engagement of elements 66 with cam surfaces 65acts to shift or cam the movable contact assembly 25, 4d, 50, 51, 52,53, S4 and 55, axially away from plate 24, so that the movable contacts50 through 55 do not engage plate 24 and the carried stationary contactsduring the major portion of the rotary movement of the movable contacts.Preferably, the proportioning of the various parts is such that themovable contacts 50 through 55 are cammed axially out of engagement withdisc 24 and the stationary contacts during the very earliest portion ofa degree shifting movement say within the iirst 5 degrees of movement.After the rotary contact structure has been turned through approximately180 degrees, elements 66 again coincide essentially with the V-shapeddetent recess formed by cam surfaces 65 of element 64, so that plates 25and 44 and the movable contacts are then freed to again shift axiallytoward plate 24 and into Contact with the stationary contacts 32 through35. Also, the engagement of elements 66 with cam surfaces 65 serves toeffectively locate and retain the rotary cam structure in its twopredetermined contacting positions which are oiset relatively 180degrees. Cam element 64 retains the rotary contact structure in itsaxially retracted position during the entire rotary movement, allowingthe movable contacts to engage the stationary contacts only at the endsof that rotary movement. In the two actuated positions 0f the switchmechanism, the movable contacts Sil through 55 are yieldingly urgedagainst and into positive engagement with the stationary contacts bysprings 59, heads 60 of the movable contacts being retracted through ashort distance axially away from plate 25.

I claim:

l. A switch for reversing an output circuit of an electrical generatorcomprising first contact means, second ccontact means mounted for rotarymovement about a predetermined axis vbetween different positionsrelative to said iirst contact means and adapted to engage said firstcontact means differently in said diiferent positions to thereby reversesaid output circuit, means for rotatively shifting said second contactmeans in opposite directions relative to the first contact means andbetween said positions in response to reversals in the direction ofrotation of said generator, and means acting to displace said first andsecond contact means relatively apart in essentially the direction ofsaid axis during said rotational shifting of the second contact meansrelative to the first.

2. A switch as recited in claim l, in which said last mentioned meanscomprise cam means acting to cam said first and second contact meansrelatively axially apart as a result of said rotary shifting of thesecond contact means.

3. A switch as recited in claim 2, in which said cam means areconstructed to function as detent means for yieldingly retaining saidsecond contact means in said dii'rerent rotary positions.

4. A switch as recited in claim 1, including a plate carrying saidsecond contact means and rotatable therewith between said differentpositions.

5. A switch as recited in claim l, including a member carrying saidsecond contact means and rotatable and axially displaceable therewithrelative to said rst contact means, and means mounting said secondcontact means for limited axial movement relative to said member.

6. A switch as recited in claim l, including a member carrying saidsecond contact means and rotatable and axially displaceable therewithrelative to said tirst contact means, means mounting said second Contactmeans for limited axial movement relative to said member, and meansyieldingly urging said second contact means axially relative to saidmember and toward said first contact means.

7. A switch as recited in claim l, including a movable member carryingsaid second Contact means and rotatable and axially displaceabletherewith, said last mentioned means of claim l comprising cam meansacting to retract said member and said carried second contact meansaxially away from said first Contact means as a result of rotaryshifting movement of said member, there being means mounting said secondcontact means for limited axial movement relative to said member, andspring means avr/fano? yieldingly urging said second contact meansaxially relative to said member and toward said first contactmeans.

8. A switch as recited in claim' 7, including additional spring meansyieldingly urging said member axially towardsaid iirstcontact means.

9. A switch ,as recited in claim l, inwhich said means for rotativelyshifting said second contact means comprise spring urged centrifugallyactuable 'pa-wl means rotating with said generator, and mea-nsconnectedto said second contact means and presenting shoulders engageable by saidpawl -means to turn said second contact means in reverse directions as.a result ofareversals'inthe direction of rotation of the generator.

110. A switch for reversing an output circuit of an electrical generatorcomprising a iirst stationary member adapted to beV mounted at alocation axially opposite an end of the generator shaft, a. plurality ofstationary contacts mounted to said rst member, a second member mountedaxially Ybetween said rst member and the `shaft and rotatable .relativetov the iirst member between two dierent positions, moveable circuitreversing contacts carried by and Irotatable with said second member andadapted to engage said stationary contacts differently in said differentrotary positions to reverse said `output circuit,- a unit to beconnected to said generator shaft land operable to rotatively shift saidsecond ,member andmovable contacts in opposite directions betweensaidvdiierent positions in response to reversal-s in the directionoirotation of the shaft, and cam means on said rst and second membersoperable to camthe latter axially away from the former during and as aresult of rotary shifting-movement of the secondmember.

1l. A switch as recited in claim 10, including means mounting saidmovable contacts for limited individual axial movement relative to saidsecond member, springs urging said movablecontacts axially relative Itosaid second member and toward the iirst member, and an additional springurging said second memberand the carried movable contacts axially towardthe Yfirst member.

12. A switch as recited in vclaim 11, in which said unit includes anelement adapted to be attached to and eX- tend outwardly in oppositedirections, from said generator shaft, and a pair of spring urgedcentrifugally actu- 3 ated pawls carried by said-element Aand adaptedtoengage coacting .shoulders on said second member to rotatively shift thelatter, there being a `pawl, .release cam carried by said iirst. member-for releasingsaid pawls from'engagement-with said-shoulders afterthe-second member reaches a predetermined one of-saidpositions.

13. A switch as. recited in claim 12, in which said cam means areconstructed to serve as detent means for yieldingly retaining saidsecond member in said rotary positions.

14. A switch as recited in claim 10, including a mountingplatey adaptedto be attached to an end of the generator for attaching the switchthereto, `means mounting said first member to said plate in outwardlyspaced relation thereto, and a-shaft projecting from said second ,membertoward said plate and mounting said second member for its rotaryshifting movement.

15. An electrical reversing switch comprising a rst section having firstandsecond contacts to be connected to, a firstl pair of external lines;said first section having a third .contact connected to said secondcontact; said section having third and; fourth contacts adapted to beconnected to a second pair-of lines; a second section having sixth,seventh, eighth, ninth, rtenth and eleventh contacts; means mounting oneof said sections for rotary movement Arelative to the otherfbetween twopredetermined positionsrelatively odset degrees; said first, second,third, founth and iifth contacts being engaged electrically with saidsixth, seventh, eighth, ninth and tenth contacts respectively in aiirstof said positions; said rst, second, third, fourth, and ifth contactsbeing engaged with said eleventh, tenth, ninth, eighth, and seventhcontacts in said second position; and means electrically connecting saidsixth contact to said ninth contact, said seventh contact to saideleventh contact, and said eighth contact to said ninth contact.

ReferencesCited in thele of this patent UNITED STATES PATENTS 796,749McElroy Aug. 8, 1905 931,613 Jackson Aug. 17, 1909 2,483,122 Bower Sept.A27, 1949 2,604,566 Callsen et al July 22, 1952

